hi bert, until will, whiteoctave, skylax, paul &c writes such a tutorial, have a look at sidgwick's greek prose composition, just put online here at textkit yesterday. he explains conditional clauses really well (he explains everything well in those first 100 pages).

Hi Bert!
Hope this helps a bit. I don't know if this is what you had in mind, it's as short as possible (I always find that short answers are good just to get an overview of the topic):

There are three conditional clauses, the Eventualis, Potentialis and the Irrealis (sorry only know the Latin terms).
It might be best if someone just checks this, because although I know how to translate these clauses into German I’m not sure that I’m doing a good job of translating them into English .

For negation use [face=spionic]mh/ [/face] in the clause and [face=spionic] ou) [/face] in the main sentence.

Eventualis:
The main body of the sentence is in future tense the clause is: [face=spionic]e)a/n [/face] + conjunctive

e.g. [face=spionic]E)a/n me a)dikh/sh|j, a)ganakth/sw.[/face] If you should do me wrong, I will (surely) be cross.

Potentialis:
The main body of the sentence is present or aorist tens and in the optative + [face=spionic]a(/n [/face] , while the clause is [face=spionic]ei) [/face] + optative aorist/present.

e.g. [face=spionic]Ei) tou kle/ptou kathgoroi~ tij, kri/noito a)/n. [/face] If someone accused a thief, he (the thief) would be condemned.

Irrealis:
This is the more complicated one...
in the present: normally the main sentence is Imperfect Indicative + [face=spionic]a)/n [/face] and the clause is [face=spionic]ei) [/face] + Imperfect Indicative. In some case though it’s the Aorist and not the indicative and still has a present tense meaning, so you just have see which translation is best.

the Irrealis of the past in normally:
main sentence is Aorist Indicative + [face=spionic]a)/n [/face] and the clause is [face=spionic]ei) [/face] + Aorist Indicative
But again a sentence in the Imperfect tense might also have a past meaning.

e.g.: [face=spionic]Ei)/ me h)di/khsaj, h)gana/kthsa a)/n.[/face] If you had done me wrong, then I would have been cross.

Most important thing to remember about the Irrealis is that it's in the Indicative, not the conjunctive like in Latin.